Optical security elements are frequently used to make it difficult to copy and misuse documents or products and if possible to prevent such copying and misuse. Thus, optical security elements are frequently used for safeguarding documents, banknotes, credit cards, cash cards and the like. In that respect it is known to use optically variable elements which cannot be duplicated with conventional copying processes. It is also known for security elements to be provided with a structured metal layer which is in the form of a text, logo or other pattern.
The production of a structured metal layer from a metal layer which is applied over a surface area for example by sputtering requires a large number of processes, in particular if fine structures are to be produced, which afford a high level of safeguard against forgery. Thus it is known for example for a metal layer which has been applied over the full surface area to be partially demetallised by positive/negative etching or by laser ablation, and thus structured. As an alternative thereto it is possible for metal layers to be already applied in structured form to a carrier by means of the use of vapour deposition masks.
The greater the number of production steps for producing the security element, the greater the significance involved in register accuracy in respect of the individual process steps.
Thus for example GB 2 136 352 A describes a production process for the production of a sealing film provided with a hologram as the security feature. In that case, a plastic film is metallised over its full surface area after embossing of a diffractive relief structure therein and is then region-wise demetallised in accurate register relationship with the embossed diffractive relief structure.